Police can't recognize every face from the vast database of criminals, but facial recognition sunglasses can—much like the ones Chinese police in Zhengzhou have been employing recently. The glasses connect to an offline 10,000-person database on a connected tablet. According to Quartz (where you can read more) a more basic version (retailing for $630 each) has been sold to the US, Japan and other countries. It's presently not known if or when they'll go into use.